bug#19802: 24.4.90; set-background-color does nothing in -nw sessions

[Eli Zaretskii <eliz@gnu.org>]

To reproduce:

  emacs -Q -nw
  M-x set-background-color RET blue RET

This appears to have no effect at all.  Even the 'background-color'
frame parameter stays at its default "unspecified-bg" value, even
though the code of set-background-color explicitly modifies the
frame's parameters:

  (defun set-background-color (color-name)
    "Set the background color of the selected frame to COLOR-NAME.
  When called interactively, prompt for the name of the color to use.
  To get the frame's current background color, use `frame-parameters'."
    (interactive (list (read-color "Background color: ")))
    (modify-frame-parameters (selected-frame)
			     (list (cons 'background-color color-name)))
    (or window-system
	(face-set-after-frame-default (selected-frame))))

Looks like this has been broken since 24.1, as the last version in
which I see it working is 23.4.  I tried both on GNU/Linux and on
MS-Windows, with the same result.


In GNU Emacs 24.4.90.4 (i686-pc-mingw32)
 of 2015-02-07 on HOME-C4E4A596F7
Repository revision: 4f5033faf26c69c123452d750bb2adfa2e77666b
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --prefix=/d/usr --enable-checking=yes,glyphs 'CFLAGS=-O0
 -g3''

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1255

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
None found.

Features:
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mm-util help-fns mail-prsvr mail-utils time-date tooltip electric
uniquify ediff-hook vc-hooks lisp-float-type mwheel dos-w32 ls-lisp
w32-common-fns disp-table w32-win w32-vars tool-bar dnd fontset image
regexp-opt fringe tabulated-list newcomment lisp-mode prog-mode register
page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock
font-lock syntax facemenu font-core frame cham georgian utf-8-lang
misc-lang vietnamese tibetan thai tai-viet lao korean japanese hebrew
greek romanian slovak czech european ethiopic indian cyrillic chinese
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer nadvice
loaddefs button faces cus-face macroexp files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process w32notify w32
multi-tty emacs)

Memory information:
((conses 8 74218 8050)
 (symbols 32 17527 0)
 (miscs 32 33 128)
 (strings 16 10779 4341)
 (string-bytes 1 269004)
 (vectors 8 9547)
 (vector-slots 4 384723 6028)
 (floats 8 57 135)
 (intervals 28 235 95)
 (buffers 508 11))